Capitalized Costs and Accumulated Depreciation, Depletion and Amortization

9 Months Ended

Sep. 30, 2013

Capitalized Costs and Accumulated Depreciation, Depletion and Amortization

(16) Capitalized Costs and Accumulated Depreciation, Depletion and Amortization (a)

	September 30, 2013			December31, 2012
	(in thousands)
Natural gas and oil properties:
Properties subject to depletion	$	7,919,627		$	7,368,308
Unproved properties		748,055			743,467
Total		8,667,682			8,111,775
Accumulated depreciation, depletion and amortization		(2,160,378	)		(2,015,591	)
Net capitalized costs	$	6,507,304		$	6,096,184

(a)Includes capitalized asset retirement costs and the associated accumulated amortization.